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                    <h1>angular2-chapter02 -- Creating and Communicating Between Components</h1>
                    
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                         作者 Guanghui Wang
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                          日期 2017-04-20
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                        <a class="tag" href="/tags/#Angular2"
                           title="Angular2">Angular2</a>
                        
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                <h1 id="Creating-and-Communicating-Between-Components"><a href="#Creating-and-Communicating-Between-Components" class="headerlink" title="Creating and Communicating Between Components"></a>Creating and Communicating Between Components</h1><p>Check code at: <a href="https://github.com/wghglory/angular2-fundamental" target="_blank" rel="noopener">https://github.com/wghglory/angular2-fundamental</a></p>
<h2 id="Creating-Our-First-Data-bound-Component"><a href="#Creating-Our-First-Data-bound-Component" class="headerlink" title="Creating Our First Data-bound Component"></a>Creating Our First Data-bound Component</h2><p>1) create events/events-list.component.ts:</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> &#123; Component &#125; <span class="keyword">from</span> <span class="string">'@angular/core'</span></span><br><span class="line"></span><br><span class="line">@Component(&#123;</span><br><span class="line">    selector: <span class="string">'events-list'</span>,</span><br><span class="line">    template: <span class="string">`</span></span><br><span class="line"><span class="string">    &lt;div&gt;</span></span><br><span class="line"><span class="string">        &lt;h1&gt;Upcoming Angular 2 Events&lt;/h1&gt;</span></span><br><span class="line"><span class="string">        &lt;div class="well hoverwell thumbnail"&gt;</span></span><br><span class="line"><span class="string">            &lt;h2&gt;Event: &#123;&#123;event.name&#125;&#125;&lt;/h2&gt;</span></span><br><span class="line"><span class="string">            &lt;div&gt;Price: \$&#123;&#123;event.price&#125;&#125;&lt;/div&gt;     //in ts file must use \$ as $!</span></span><br><span class="line"><span class="string">            &lt;div&gt;Date: &#123;&#123;event.date&#125;&#125;&lt;/div&gt;</span></span><br><span class="line"><span class="string">            &lt;div&gt;Time: &#123;&#123;event.time&#125;&#125;&lt;/div&gt;</span></span><br><span class="line"><span class="string">            &lt;div&gt;Address: &#123;&#123;event.location.address&#125;&#125;, &#123;&#123;event.location.city&#125;&#125;, &#123;&#123;event.location.country&#125;&#125;&lt;/div&gt;</span></span><br><span class="line"><span class="string">        &lt;/div&gt;</span></span><br><span class="line"><span class="string">    &lt;/div&gt;</span></span><br><span class="line"><span class="string">    `</span></span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">EventsListComponent</span> </span>&#123;</span><br><span class="line">    event = &#123;</span><br><span class="line">        name: <span class="string">'ngConf 2025'</span>,</span><br><span class="line">        date: <span class="string">'3/1/2025'</span>,</span><br><span class="line">        time: <span class="string">'8am'</span>,</span><br><span class="line">        price: <span class="string">'599'</span>,</span><br><span class="line">        location: &#123; <span class="attr">address</span>: <span class="string">'123 Main St'</span>, <span class="attr">city</span>: <span class="string">'Salt Lake City, UT'</span>, <span class="attr">country</span>: <span class="string">'USA'</span> &#125;</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>2) modify app.component.ts:</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> &#123; Component &#125; <span class="keyword">from</span> <span class="string">'@angular/core'</span></span><br><span class="line"></span><br><span class="line">@Component(&#123;</span><br><span class="line">    selector: <span class="string">'events-app'</span>,</span><br><span class="line">-    <span class="comment">// template: '&lt;h2&gt;hello world&lt;/h2&gt;'</span></span><br><span class="line">+    template: <span class="string">'&lt;events-list&gt;&lt;/events-list&gt;'</span></span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">AppComponent</span> </span>&#123;&#125;</span><br></pre></td></tr></table></figure>
<p>3) update module:</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> &#123; NgModule &#125; <span class="keyword">from</span> <span class="string">'@angular/core'</span></span><br><span class="line"><span class="keyword">import</span> &#123; BrowserModule &#125; <span class="keyword">from</span> <span class="string">'@angular/platform-browser'</span></span><br><span class="line"></span><br><span class="line"><span class="keyword">import</span> &#123; AppComponent &#125; <span class="keyword">from</span> <span class="string">'./app.component'</span></span><br><span class="line">+ <span class="keyword">import</span> &#123; EventsListComponent &#125; <span class="keyword">from</span> <span class="string">'./events/events-list.component'</span></span><br><span class="line"></span><br><span class="line">@NgModule(&#123;</span><br><span class="line">    imports: [BrowserModule],</span><br><span class="line">+   declarations: [AppComponent, EventsListComponent],</span><br><span class="line">    bootstrap: [AppComponent]</span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">AppModule</span> </span>&#123;&#125;</span><br></pre></td></tr></table></figure>
<h2 id="Using-External-Templates"><a href="#Using-External-Templates" class="headerlink" title="Using External Templates"></a>Using External Templates</h2><p>1) create events-list.component.html as template:</p>
<figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;<span class="name">h1</span>&gt;</span>Upcoming Angular 2 Events<span class="tag">&lt;/<span class="name">h1</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"well hoverwell thumbnail"</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">h2</span>&gt;</span>Event: &#123;&#123;event.name&#125;&#125;<span class="tag">&lt;/<span class="name">h2</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">div</span>&gt;</span>Price: $&#123;&#123;event.price&#125;&#125;<span class="tag">&lt;/<span class="name">div</span>&gt;</span>  <span class="comment">&lt;!-- no need \$ --&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">div</span>&gt;</span>Date: &#123;&#123;event.date&#125;&#125;<span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">div</span>&gt;</span>Time: &#123;&#123;event.time&#125;&#125;<span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">div</span>&gt;</span>Address: &#123;&#123;event.location.address&#125;&#125;, &#123;&#123;event.location.city&#125;&#125;, &#123;&#123;event.location.country&#125;&#125;<span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<p>2) modify events-list.component.ts using templateUrl instead of template:</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> &#123; Component &#125; <span class="keyword">from</span> <span class="string">'@angular/core'</span></span><br><span class="line"></span><br><span class="line">@Component(&#123;</span><br><span class="line">    selector: <span class="string">'events-list'</span>,</span><br><span class="line">-    <span class="comment">// template: ``</span></span><br><span class="line">+    templateUrl: <span class="string">'app/events/events-list.component.html'</span>   <span class="comment">//relative to index.html</span></span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">EventsListComponent</span> </span>&#123;</span><br><span class="line">    event = &#123;</span><br><span class="line">        name: <span class="string">'ngConf 2025'</span>,</span><br><span class="line">        date: <span class="string">'3/1/2025'</span>,</span><br><span class="line">        time: <span class="string">'8am'</span>,</span><br><span class="line">        price: <span class="string">'599'</span>,</span><br><span class="line">        location: &#123; <span class="attr">address</span>: <span class="string">'123 Main St'</span>, <span class="attr">city</span>: <span class="string">'Salt Lake City, UT'</span>, <span class="attr">country</span>: <span class="string">'USA'</span> &#125;</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<h2 id="Components-Interaction"><a href="#Components-Interaction" class="headerlink" title="Components Interaction"></a>Components Interaction</h2><h3 id="1-Communicating-with-Child-Components-Using-Input-Parent-pass-data-to-child"><a href="#1-Communicating-with-Child-Components-Using-Input-Parent-pass-data-to-child" class="headerlink" title="1. Communicating with Child Components Using @Input (Parent pass data to child)"></a>1. Communicating with Child Components Using @Input (Parent pass data to child)</h3><p>I want to create a address component as a child component. The parent component, events-list, will pass the event object to the child. To get this done:</p>
<ul>
<li>child component needs import Input from angular/core</li>
<li>parent template uses the child selector, and [child object name] = “parent”</li>
</ul>
<p>1) create child component events-address.component.ts</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">//child component, talk with parent events-list.component.ts</span></span><br><span class="line"><span class="keyword">import</span> &#123;Component,Input&#125; <span class="keyword">from</span> <span class="string">'@angular/core'</span></span><br><span class="line"></span><br><span class="line">@Component(&#123;</span><br><span class="line">    selector: <span class="string">'events-address'</span>,</span><br><span class="line">    template: <span class="string">'&lt;span&gt;&#123;&#123;address.address&#125;&#125;,&#123;&#123;address.city&#125;&#125;,&#123;&#123;address.country&#125;&#125;&lt;/span&gt;'</span></span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">EventsAddressComponent</span></span>&#123;</span><br><span class="line">    @Input() address:any  <span class="comment">//define address object</span></span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>2) modify parent component template, [address] is child object name, “event.location” is parent data</p>
<figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;<span class="name">h1</span>&gt;</span>Upcoming Angular 2 Events<span class="tag">&lt;/<span class="name">h1</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"well hoverwell thumbnail"</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">h2</span>&gt;</span>Event: &#123;&#123;event.name&#125;&#125;<span class="tag">&lt;/<span class="name">h2</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">div</span>&gt;</span>Price: $&#123;&#123;event.price&#125;&#125;<span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">div</span>&gt;</span>Date: &#123;&#123;event.date&#125;&#125;<span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">div</span>&gt;</span>Time: &#123;&#123;event.time&#125;&#125;<span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">        <span class="comment">&lt;!-- &lt;div&gt;Address: &#123;&#123;event.location.address&#125;&#125;, &#123;&#123;event.location.city&#125;&#125;, &#123;&#123;event.location.country&#125;&#125;&lt;/div&gt; --&gt;</span></span><br><span class="line">        <span class="tag">&lt;<span class="name">events-address</span> [<span class="attr">address</span>]=<span class="string">"event.location"</span>&gt;</span><span class="tag">&lt;/<span class="name">events-address</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<p>3) import child component to app.module</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> &#123; EventsAddressComponent &#125; <span class="keyword">from</span> <span class="string">'./events/events-address.component'</span></span><br><span class="line"></span><br><span class="line">@NgModule(&#123;</span><br><span class="line">    declarations: [AppComponent, EventsListComponent, EventsAddressComponent],</span><br><span class="line">&#125;)</span><br></pre></td></tr></table></figure>
<h3 id="2-Communicating-with-Parent-Components-Using-Output-and-EventEmitter-child-pass-data-to-parent"><a href="#2-Communicating-with-Parent-Components-Using-Output-and-EventEmitter-child-pass-data-to-parent" class="headerlink" title="2. Communicating with Parent Components Using @Output and EventEmitter (child pass data to parent)"></a>2. Communicating with Parent Components Using @Output and EventEmitter (child pass data to parent)</h3><p>1) child component “events-address.component.ts”:</p>
<ul>
<li>import Output, EventEmitter</li>
<li>define a variable accepting EventEmitter</li>
<li>define buttonClick</li>
<li>the EventEmitter variable emit any data from child component</li>
</ul>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">//child component, talk with parent events-list.component.ts</span></span><br><span class="line"><span class="keyword">import</span> &#123;Component, Output, EventEmitter&#125; <span class="keyword">from</span> <span class="string">'@angular/core'</span></span><br><span class="line"></span><br><span class="line">@Component(&#123;</span><br><span class="line">    selector: <span class="string">'events-address'</span>,</span><br><span class="line">    template: <span class="string">'&lt;button (click)="buttonClick()"&gt;Click me!&lt;/button&gt;'</span></span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">EventsAddressComponent</span></span>&#123;</span><br><span class="line">    @Output() myclick = <span class="keyword">new</span> EventEmitter()</span><br><span class="line"></span><br><span class="line">    buttonClick()&#123;</span><br><span class="line">        <span class="keyword">this</span>.myclick.emit(<span class="string">'I am from child component, should pass data to parent component'</span>)</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>2) parent Component “events-list.component.ts”:</p>
<ul>
<li><p>update template: (the EventEmitter variable name defined in child component) = “randomFuncInParent($event)”</p>
  <figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">events-address</span> (<span class="attr">myclick</span>)=<span class="string">"clickWithAnyName($event)"</span>&gt;</span><span class="tag">&lt;/<span class="name">events-address</span>&gt;</span></span><br></pre></td></tr></table></figure>
</li>
<li><p>define random function in parent component class</p>
  <figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">EventsListComponent</span> </span>&#123;</span><br><span class="line">    clickWithAnyName(dataFromChild)&#123;</span><br><span class="line">        alert(dataFromChild)</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
</li>
</ul>
<h3 id="3-Using-Template-Variables-To-Interact-with-Child-Components-parent-access-to-child-data-easier-than-method-2"><a href="#3-Using-Template-Variables-To-Interact-with-Child-Components-parent-access-to-child-data-easier-than-method-2" class="headerlink" title="3. Using Template Variables To Interact with Child Components (parent access to child data, easier than method 2)"></a>3. Using Template Variables To Interact with Child Components (parent access to child data, easier than method 2)</h3><p>1) child component events-address.component.ts define public property and method</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">//child component, talk with parent events-list.component.ts</span></span><br><span class="line">@Component(&#123;</span><br><span class="line">    selector: <span class="string">'events-address'</span>,</span><br><span class="line">    template: <span class="string">''</span></span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">EventsAddressComponent</span> </span>&#123;</span><br><span class="line">    <span class="comment">//use template variable to interact with child public method/property: parent accesses child data</span></span><br><span class="line">    author:string = <span class="string">'Guanghui Wang'</span>  <span class="comment">//child public property</span></span><br><span class="line">    getAuthor()&#123;</span><br><span class="line">        alert(<span class="keyword">this</span>.author)</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>2) access child component data from parent component template’s childPointer variable</p>
<figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">events-address</span> [<span class="attr">address</span>]=<span class="string">"event.location"</span> (<span class="attr">myclick</span>)=<span class="string">"clickWithAnyName($event)"</span> #<span class="attr">childPointer</span>&gt;</span><span class="tag">&lt;/<span class="name">events-address</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;<span class="name">button</span> (<span class="attr">click</span>)=<span class="string">"childPointer.getAuthor()"</span> <span class="attr">class</span>=<span class="string">"btn-primary btn"</span>&gt;</span>Test template variable<span class="tag">&lt;/<span class="name">button</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;<span class="name">h3</span>&gt;</span>&#123;&#123;childPointer.author&#125;&#125;<span class="tag">&lt;/<span class="name">h3</span>&gt;</span></span><br></pre></td></tr></table></figure>
<h2 id="Styling-Components"><a href="#Styling-Components" class="headerlink" title="Styling Components"></a>Styling Components</h2><blockquote>
<p>By default, style scope is current component: the class defined below works only in current component, any other component applied same class won’t work.</p>
<p>Global css can be placed in styles.css</p>
</blockquote>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">@Component(&#123;</span><br><span class="line">    template: <span class="string">`&lt;button class="mybutton"&gt;styling component&lt;/button&gt;`</span>,</span><br><span class="line">    styles: [<span class="string">`.mybutton&#123;background:purple;&#125;`</span>]</span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">EventsAddressComponent</span> </span>&#123;&#125;</span><br></pre></td></tr></table></figure>
<h2 id="Create-Navbar"><a href="#Create-Navbar" class="headerlink" title="Create Navbar"></a>Create Navbar</h2><p>create nav/nav.component.ts and its template nav.component.html, then export component into module.</p>
<figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> &#123;Component&#125; <span class="keyword">from</span> <span class="string">'@angular/core'</span></span><br><span class="line"></span><br><span class="line">@Component(&#123;</span><br><span class="line">    selector: <span class="string">'nav-bar'</span>,</span><br><span class="line">    templateUrl: <span class="string">'app/nav/nav.component.html'</span>,</span><br><span class="line">    styles: [<span class="string">`</span></span><br><span class="line"><span class="string">        .nav.navbar-nav &#123;font-size:15px;&#125;</span></span><br><span class="line"><span class="string">        #searchForm &#123;margin-right:100px;&#125;</span></span><br><span class="line"><span class="string">        @media(max-width:1200px) &#123;#searchForm &#123;display:none;&#125;&#125;</span></span><br><span class="line"><span class="string">    `</span>]</span><br><span class="line">&#125;)</span><br><span class="line"><span class="keyword">export</span> <span class="class"><span class="keyword">class</span> <span class="title">NavBarComponent</span> </span>&#123; &#125;</span><br></pre></td></tr></table></figure>

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                    <ol class="toc"><li class="toc-item toc-level-1"><a class="toc-link" href="#Creating-and-Communicating-Between-Components"><span class="toc-text">Creating and Communicating Between Components</span></a><ol class="toc-child"><li class="toc-item toc-level-2"><a class="toc-link" href="#Creating-Our-First-Data-bound-Component"><span class="toc-text">Creating Our First Data-bound Component</span></a></li><li class="toc-item toc-level-2"><a class="toc-link" href="#Using-External-Templates"><span class="toc-text">Using External Templates</span></a></li><li class="toc-item toc-level-2"><a class="toc-link" href="#Components-Interaction"><span class="toc-text">Components Interaction</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#1-Communicating-with-Child-Components-Using-Input-Parent-pass-data-to-child"><span class="toc-text">1. Communicating with Child Components Using @Input (Parent pass data to child)</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#2-Communicating-with-Parent-Components-Using-Output-and-EventEmitter-child-pass-data-to-parent"><span class="toc-text">2. Communicating with Parent Components Using @Output and EventEmitter (child pass data to parent)</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#3-Using-Template-Variables-To-Interact-with-Child-Components-parent-access-to-child-data-easier-than-method-2"><span class="toc-text">3. Using Template Variables To Interact with Child Components (parent access to child data, easier than method 2)</span></a></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#Styling-Components"><span class="toc-text">Styling Components</span></a></li><li class="toc-item toc-level-2"><a class="toc-link" href="#Create-Navbar"><span class="toc-text">Create Navbar</span></a></li></ol></li></ol>
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